Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA.
Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.
Sci Adv. 2020 Jan 24;6(4):eaax8787. doi: 10.1126/sciadv.aax8787. eCollection 2020 Jan.
Protists are ubiquitous in soil, where they are key contributors to nutrient cycling and energy transfer. However, protists have received far less attention than other components of the soil microbiome. We used amplicon sequencing of soils from 180 locations across six continents to investigate the ecological preferences of protists and their functional contributions to belowground systems. We complemented these analyses with shotgun metagenomic sequencing of 46 soils to validate the identities of the more abundant protist lineages. We found that most soils are dominated by consumers, although parasites and phototrophs are particularly abundant in tropical and arid ecosystems, respectively. The best predictors of protist composition (primarily annual precipitation) are fundamentally distinct from those shaping bacterial and archaeal communities (namely, soil pH). Some protists and bacteria co-occur globally, highlighting the potential importance of these largely undescribed belowground interactions. Together, this study allowed us to identify the most abundant and ubiquitous protists living in soil, with our work providing a cross-ecosystem perspective on the factors structuring soil protist communities and their likely contributions to soil functioning.
原生动物在土壤中无处不在，它们是养分循环和能量转移的关键贡献者。然而，与土壤微生物组的其他组成部分相比，原生动物受到的关注要少得多。我们使用来自六大洲 180 个地点的土壤扩增子测序来研究原生动物的生态偏好及其对地下系统的功能贡献。我们通过对 46 个土壤的鸟枪法宏基因组测序对这些分析进行了补充，以验证更丰富的原生动物谱系的身份。我们发现，大多数土壤主要由消费者主导，尽管寄生虫和光合生物分别在热带和干旱生态系统中特别丰富。预测原生动物组成（主要是年降水量）的最佳指标与塑造细菌和古菌群落的指标（即土壤 pH 值）从根本上不同。一些原生动物和细菌在全球范围内共同出现，这突出了这些在很大程度上尚未描述的地下相互作用的潜在重要性。总的来说，这项研究使我们能够识别出在土壤中生活的最丰富和最普遍的原生动物，我们的工作为土壤原生动物群落结构的因素提供了一个跨生态系统的视角，并可能对土壤功能做出贡献。
